Isomerization of terminal olefins



1968 w. F. WOLFF 3,405,196

ISOMERIZATION OF TERMINAL OLEFINS Filed April 10, 1967 ProductSeparafion ga f /Z73 And Recovery Hydrocarbons 0 lnerf Gas 0 OxygenContai i INVENTOR.

Gas William F. Wolff United States Patent 3,405,196 ISOMERIZATION OFTERMINAL OLEFINS William F. Wolff, Park Forest, Ill., assignor toStandard Oil Company, Chicago, Ill., a corporation of IndianaContinuation-impart of application Ser. No. 354,417, Mar. 24, 1964. Thisapplication Apr. 10, 1967, Ser. No. 629,617

10 Claims. (Cl. 260683.2)

ABSTRACT OF THE DISCLOSURE Catalyst-preparation method wherein acatalyst comprising an alkali metal dispersed upon a high-surface,substantially inert, solid support is contacted with an activating gasat a temperature between about 5 C. and about 50 C. in sufiicientquantity to provide an oxygen-to-alkali metal ratio between about 0.01and 2.0 atoms of oxygen per atom of alkali metal. The activating gas isselected from a molecular-oxygen-containing gas, nitrous oxide, mixturesthereof, and mixtures thereof with inert gases.

Cross-references to related applications This is a continuation-in-partapplication of application Ser. No. 354,417, filed Mar. 24, 1964 and nowabandoned.

Background of the invention This invention pertains to a process for theconversion of hydrocarbons, which process is directed to the molecularrearrangement of olefin hydrocarbons. The process employs a catalystwhich is a composition containing significant amounts of an alkali metalor a compound thereof.

Summary of the invention This invention relates to a process for theconversion 0 fa terminal olefin to an internal olefin. Moreparticularly, it relates to an improved process for the isomerization ofa terminal olefinic hydrocarbon in which the double bond is shifted fromthe terminal position to a morecentrally-located position. Still moreparticularly, it relates to the conversion of pentene-l to pentene-2 andbutene-l to butene-2.

The development and production of automobile engines which have highcompression ratios have resulted in the necessity of hydrocarbons whichhave antiknock characteristics. One of the many petroleum refiningprocesses which produce high antiknock hydrocarbons is the catalyticalkylation of isoparaffin hydrocarbons with olefins. Olefins which havetheir double bonds more centrally located in the molecule producehigher-octane alkylate. Hence, this type of olefin is desirable. Myprocess will efficiently produce those olefins which are desirable foralkylation feed.

My process comprises an improved process for the production of internalolefins from terminal olefins in which an improved catalyst is employed.It is known in the art that terminal olefinic hydrocarbons can havetheir double bonds shifted to a more-centrally-located position in thepresence of a supported alkali-metal catalyst. This has been disclosedin US. Patent 2,965,689 and U.S. Patent 2,952,719. My improved catalystis a supported alkalimetal catalyst which has seen a specificpretreatment and which can be used for the conversion of terminalolefins to internal olefins, for the preparation of alkylation feed andfor the production of chemical intermediates. Much improved yields ofthe internal olefinic hydrocarbons result when my process is used ratherthan the presently available processes.

My improved process comprises shifting the double bond in a terminalolefinic hydrocarbon to a more-centrally-located position in thepresence of a supported alkalimetal catalyst that has been pretreated inan activating atmosphere. The improvement of this process comprises thepretreating of the catalyst with an activating gas prior to the use ofthe catalyst in the conversion process.

One embodiment of my invention is a process in which the double bond ina terminal olefinic hydrocarbon is shifted to a more-centrally-locatedposition in the molecule in the presence of a supported alkali-metalcatalyst that has been pretreated with a gas that contains molecularoxygen.

Another embodiment is a process in which a terminal olefin is convertedto an internal olefin in the presence of a supported alkali-metalcatalyst that has been pretreated with a gas that contains nitrousoxide.

The catalyst used in my process contains an alkali metal dispersed on ahigh-surface, substantially inert support. The alkali metal may beselected from a group comprising sodium, potassium, rubidium and cesium.Sodium is particularly desirable. The supporting material should possessa high surface area, large pores, and be only slightly acidic. Thesupporting material should be calcined to drive out the water. Thiscalcination may be carried out at temperatures of from 150 to 650 C.,450 to 600 C. being particularly desirable, and a pressure of from 0.1mm. of mercury to 1.0 atmosphere for 0.1 to 50 hours. The supportingmaterial is desirable in a granular or powdered form. Activated aluminais a particularly desirable supporting material.

This alumina generally has a surface area ranging from about 50 to 1,000square meters per gram. The alumina used in the preparation of thecatalyst employed in the tests mentioned below has a surface area of200-210 square meters per gram, a packed bulk density of 68 pounds percubic feet and a particle size of -200 mesh. This granular alumina hasan ignition loss of 6.8% at 1100 F. and is composed of 92.0% A1 0 0.8%Na O, approximately 0.1% SiO and approximately 0.1% F6203.

The supported alkali metal catalyst is prepared by contacting the highsurface area supporting material with the alkali metal while the latteris in the molten state. This contactingis done in the presence ofagitation under an inert atmosphere, such as argon, nitrogen or helium.This so-called inert atmosphere must be such that it will not react withthe alkali metal to transform the alkali metal into a derivative thatwill not catalyze isomerization. The alkali metal may be added to thecalcined support at a temperature of from 10 to 35 C. under an inertatmosphere. The resulting mixture is then heated to a temperature offrom to 500 C., 300 to 400 C. being particularly desirable. The mixtureis continuously agitated at the elevated temperature until the alkalimetal appears to'be evenly distributed upon the surface of thesupporting material. Even distribution usually will be attained within aperiod of from approximately 10 minutes to approximately 2 hours. Ifsodium is being distributed on activated alumina, a uniform layer ofsodium is indicated by a blue-black color which occurs over the entiresurface of the alumina. The catalyst may contain between about 1 and 40%by weight of the alkali metal, depending upon the particular alkalimetal and the particular supporting material employed. Generally, thatamount of alkali metal whichis suflicient to form a mono-molecular layeron the support is desired. When sodium is to be on activated alumina,the resulting catalyst will usually contain from 2 to 15% by weight ofsodium.

The improvement of my process comprises the pretreating of the supportedalkali-metal catalyst with an activating gas at a temperature within therange of from 5 to 50 C., 20 to 35 C. being particularly desirable.Preferably a positive flow of the activating gas through the catalystbed is maintained. Care should be taken during the pretreatment to avoidgeneral or localized overheating of the catalyst. The activating gas isselected from the group consisting essentially of amolecularoxygen-containing gas, nitrous oxide (N mixtures thereof andmixtures thereof with inert gases. These inert gases are gases whichwill not chemically react with the sodium, e.g., nitrogen, argon, neonand helium. It is desirable that the activating gas be used in an amountwhich is suflicient to provide a quantity of oxygen which will furnishan oxygen-to-alkali-metal ratio within the range between about 0.01 and2.0 atoms of oxygen per atom of alkali metal. Of course, the atoms ofoxygen would be the atoms of oxygen in the activating gas and the atomsof sodium are the atoms of sodium present in the catalyst that is beingused to isomerize the terminal olefins. Preferably, the quantity ofactivating gas should be maintained at a level which will provide anoxygen-toalkali-metal ratio within the range between 0.1 and 0.4 atom ofoxygen per atom of alkali metal. The rate of flow of the activating gasshould be maintained at a level which will not result in the creation ofexcessive temperatures.

Brief description of the drawing My process will be more fullyunderstood with reference to the examples and the drawing which follow.The drawing exemplifies a specific embodiment of a proposed installationof my process and is a simplified diagrammatic representation of thisembodiment.

Description of the preferred embodiments Various hydrocarbon feed stocksmay be used in my process. These comprise the alpha-olefins such asbutene- 1, pentene-l, hexene-l and similar olefins. In addition, aliquified mixture of butanes and butenes which are recovered from theproducts of catalytic cracking and/ or thermal cracking of gas oils, orfrom the products of other refinery operations, may be used. Thecomposition of such a refinery stream may be widely variable, theproducing sources dictating such composition. This mixture is commonlyreferred to as a refinery BB stream. Furthermore, organic compounds suchas 1- phenyl butene 1, 2 phenyl butene 1, 1 phenylpentene 1 and 4 tolylpentene 1 may also be used as feed stocks in my process. Since water hasa deleterious effect upon the alkali-metal catalyst, drying of the feedstock is particularly desirable before the feed stock is contacted withthe catalyst.

The isomerization of the terminal olefin, or mixture of olefins, can beperformed as either a batch, continuous or semi-continuous process. Afixed, moving or fluidized catalyst bed may be employed; and thecontacting of the catalyst with the hydrocarbons may be performed eitherin the presence of or the absence from a diluent that is substantiallyinert with respect to the catalyst under the conditions employed. Theisomerization of the alphaolefins may be carried out at relatively lowpressures, but pressures up to approximately 100 to 350 p.s.i.g. may beused to keep the lower boiling olefins in the liquid state. It isparticularly desirable that the hydrocarbon feed be kept in the liquidstate. Temperatures ranging from 80 C. to 100 C. are usually employed.The temperature at which the isomerization is to be conducted will bedictated by the equilibrium between the olefin charge and the desiredolefin isomer or isomers. For example, when butene-1 is being convertedto butene-2, a temperature that does not exceed 30 C. is preferred. Therelatively high activity of this type of catalyst permits the use oftemperatures well below room temperature while satisfactory reactionrates are being maintained.

The following examples are presented to illustrate specific embodimentsof my process, but it is not intended that these examples unduly limitthe scope of my invention.

. EXAMPLE I v This example illustrates the use of air as the activatinggas. A B-necked, 200milliliter flask was fitted with a stainless steelstirrer and a gas-inlet valve. Into it were charged 30.0 grams of the80-200 mesh activated alumina which has been described above. Thealumina was heated with stirring under a stream ofargon until the skintemperature of the flask reached 710 C. The source of heat was removedand the dry alumina was cooled to atemperature of approximately 24 C.Under argon, 4.1 grams of sodium metal were added. The sodium was cutand Weighed while in a paraffinic oil. The mixture was then heated withstirring under a static argon blanket until the skin temperature of theflask reached 410 C. This latter temperature was maintained for 40minutes. The product, a dark blue solid, was then cooled to atemperature of approximately 24 C. A 3.2-gram portion of thissodium-on-alumina preparation was taken from the flask and was placed inan Emulsion Tube. It was then exposed to air until a definitetemperature rise, as determined by touch, was obtained. The catalystsample was purged with nitrogen and then added to 100 cc. of pentene-lthat had been dried previously by stirring with sodium-mercury amalgam.The amalgam was not subsequently removed from the olefin. Stirring wascontinued after the catalyst addition and a blanket of nitrogen wasmaintained over the reaction mixture. With the mixture being held at atemperature of approximately 24 C., samples of the liquid, approximatingone-half cc. each, were withdrawn periodically. Immediately uponwithdrawal, each liquid sample was completely distilled from the samplevial to a clean vial to permit removal of catalyst traces. Thisdistillation was accomplished by connecting the sample vial to the cleanvial by means of an extended piece of polyethylene tubing. The cleanvial was cooled in liquid nitrogen while the sample vial was warmed bythe heat from the experimenters'hand. Such distillations requiredapproximately 4 minutes apiece. The samples were then analyzed by gaschromatography. The results obtained from these analyses are presentedin Table I.

TABLE I Time from catalyst addition,

A 3.1-gram portion of the sodium-on-alumina catalyst was removed fromthe preparation flask and was maintained under an inert atmosphere. Thissample was not exposed to air and was added to 100 cc. of pentene-l asabove. The results obtained ase presented in Table II.

TABLE II Time from catalyst addition, Percent pentene-l Percentpentene-2 minutes These results show that sodium deposited on alumina isa good catalyst for the isomerization of a terminal olefin but that acatalyst prepared and used according to my process is much more active.The results indicate that after 15 minutes, the conversion with theair-treated sodium-on-alumina catalyst is at least 9 times as great asthat obtained with the untreated sodium-on-alumina catalyst. 7

5 EXAMPLE n This example illustrates that at specific pretreatments ofthe catalyst with the activating gas, optimum results unsuccessful, suchtreatment resulting in a decrease in can be obtained. It furtherillustrates that treatment with g y f h 1 too much activating gas, aswell as too little activating 5 a i lmfirovement re ative p gas, doesnot provide the best activity of the catalyst for gccurre 8 en g f i whowas mamtalged converting terminal olefins to internal olefins. In thisgtween an f 3 en example, isomerization runs were carried out withcatoxygen mm who was 0W as an alyst treated with measured amounts of dryair. Runs hlgh Therefore the treaiment of catalyst with were carried outat c 5 C and C and the activating gas must be sufiicient to provide anoxygenwith olefin charges of different purity. Except as other to-sodiumratio wlthm the range between about 0.01 and wise noted, theexperimental procedures described in atoms of oxygen. per atom of Sodiumprfa'ferably Example I were used. The catalyst was either sodiumh amountacnvatmg gas to be.used suffi' on-alumina or sodium-on-charcoal. Thecatalyst to be Clem to Provlde an oxygen'to'sodlum Wlthm the added tothe olefin was treated with air in the sample rzngedpetween and atoms ofoxygen per atom tube by pumping a measured amount of dry air into the 0EXAMPLE HI tube against a slight nitrogen pressure. The air wasintroduced, with continual shaking of the tube, at such a This exampleillustrates the treatment of the catalyst rate that the catalyst becamewarm, but not hot, to the with air after isomerization has beeninitiated. A run was touch. The small amounts of air were dried wlthindicatcarried out at C. in which an untreated sodium-oning Drieritewhile the large amounts of air were dried alumina catalyst, prepared asabove, was used and air by passage through two Drierite columns, one ofwhich was slowly introduced into the reaction flask after isomerwas keptat 78 C. The olefin used in this series of ization had begun. Noincrease in isomerization rate was tests was again pentene-l, and theresults of this series 5 obtained; rather the rate decreasedconsiderably more are given in the following table: 2 rapidly than inthe case of runs carried out under an TABLE III Vol. of air Oxygen-to-Maximum used in cat. sodium ratio, Olefin purity, Temperature, relativeCatalyst treatment, atoms oxygen percent 0. reaction oeJg. eat. per atompentene-l rate sodium 0 o. 00 100. 0 -7s 0. 7 45 0.14 100.0 -73 270 3100. 97 100. 0 -7s 32 0 0. 00 99.8 25 15 5 0. 010 99.8 25 s 10 0. 032 99.925 0 00 0.19 99.8 25 2 1 No sodium-mercury amalgam was used in this run.Pentene-l was dried over sodium wire; reaction flask was dried byheating prior to the run.

The volumes of air were measured at 24 C. and approximately 1 atmospherepressure. The activities of the various catalysts are compared in termsof the maximum rate at which they converted the pentene-l intopentene-2, as measured over a period of at least 5 min utes. Thereaction rates were expressed in terms of the pentene-l consumed pergram of catalyst per minute. In the low-temperature runs, sodium mercuryamalgam was stirred with the pentene-l at room temperature for at least/2 hour before cooling the olefin to reaction temperature. The amalgamwas left in the mixture. The catalyst was also cooled to the reactiontemperature before it was added to the olefin. Samples that werewithdrawn for analysis were introduced into vials containing distilledwater so that no additional isomerization of the samples would occurafter withdrawal from the reaction mixture.

The calculated ratio of atoms of oxygen to atoms of sodium is presentedin column 3 of the Table III for each datum point. The atoms of sodiumused in the calculations of these values represent the actual amount ofsodium introduced onto the support and not the amount present after theimpurities in the support have reacted with the sodium.

The results of this example show that optimum results may be obtained ifthe sodium-on-alumina catalyst is treated with limited, but substantial,amounts of air. Treatment of the catalysts with excess lair producedcatalysts which were superior to the original sodium-on-alumina catalystbut which were inferior to the catalysts treated with the optimumamounts of air. In all cases, the airtreated catalysts were shown to besuperior to the tininert atmosphere. Furthermore, after a short time,the isomerization stopped completely.

EXAMPLE IV This example illustrates the treatment of the catalyst withdi-butyl peroxide after isomerization has been initiated. Even thoughonly 0.5 cc. of di-t-butyl peroxide was added to the pentene-l afterisomerization had begun over an untreated sodium-on-alumina catalyst, analmost immediate deactivation of the catalyst was obtained. Theuntreated catalyst had been prepared as described above.

EXAMPLE V This example illustrates the isomerization of butenes with anair-treated catalyst. A 0.58-gram portion of sodiurn-on-alumina catalystwas shaken with 20 cc. of dry air which were added in 2-cc. increments.The addition of the air was brought about by the removal of the gas froma burette by mercury displacement. The calculated oxygen-to-sodium ratiofor this treatment was 0.21 atom of oxygen per atom of sodium. Thesodium-on-alumina catalyst had been prepared as described above bydepositing 2.1 grams of sodium metal on 30 grams of alumina. Thisair-treated sodium-on-alumina catalyst was then added to milliliters ofliquid butene-l. This mixture Was refluxed at atmospheric pressure andstirred with a magnetic stirrer. A sample of the hydrocarbon wasWithdrawn after 5 minutes and was analyzed by gas chromatography. Theanalysis showed a 27.3% conversion of butene-l to butene-2.

A 0.59-gram portion of the sodium-on-alumina catalyst prepared for thisexample was added to another 100 milliliter portion of liquid butene-lwith similar refluxing and stirring. In this case, the sodium-on-aluminacatalyst had seen no prior air treatment. Analysis showed only a 1.9%conversion of butene-l to buten e-Z. The results of this example show,as those in the examples above, that the air treatment substantiallyincreases the isomerization rate.

EXAMPLE VI This example illustrates the pretreating of asodium-onalumina catalyst with nitrous oxide. Thealkali-metal-containing catalyst received a treatment in nitrous oxide.Alumina, having the properties specified above, was heated to about 700C. (skin temperature of container) under a stream of argon and was thencooled. After cooling, 7.0 grams of sodium metal were deposited on 60grams of this 80-200-mesh alumina. The sodium and the alumina werestirred together at skin temperatures not exceeding 400 C. until auniform blue-black product was obtained. About 3.2 cc. (2.9 grams) ofthis product were charged to an Emulsion Tube which had been fitted witha gas inlet tube and which had been dried previously by heating. Thischarging was carried out under a ni.rogen atmosphere. After charging, 20cc. of nitrous oxide were pumped into the tube with shaking in 2-cc.increments. The calculated oxygen-to-sodium ratio for this treatment was0.062 atom of oxygen per atom of sodium. This value falls within therange established in Example II, which range is between 0.01 and 2.0atoms of oxygen per atom of sodium. In oiher words, the oxygen atoms inthe nitrous oxide molecules were sufiicient to provide the abovecalculated oxygen-to-sodium ratio. Mercury displacement was again usedto force the gas into the tube. Some heat evolution and whitening of thecatalyst were observed. The catalyst was then added to 100 millilitersof pentene-l in an ice bath. The pentene-1 was stirred with a magneticstirrer under a nitrogen atmosphere. Small portions of the pentene wereremoved periodically, added immediately to water and measured for theirrespective refractive indices. The following results were obtained.

Time (minutes) Refractive index N 1.3714 N 1.3761 M32035: 1.3791 NDZO-:1.3811 30 N 9 1.3813 N 1.3812 N 9 1.3810

The initial rate of isomerization, as measured by the increase inrefractive index per gram of catalyst per minute, was 3.'22 lO When thesame catalyst, but untreated with nitrous oxide, was used, the increasein the initial rate of isomerization was 0.60 X 10 and in duplicateruns. This example demonstrates that a sodium-on-alumina catalystpretreated with nitrous oxide is superior to an untreated catalyst forolefin isomerization.

A further understanding of my process may be gained from the specificembodiment exemplified by the following proposed installation, which isdiagrammed in the attached figure. The desired supported alkali-metalcatalyst, a sodium-o'n-alumina catalyst, is charged under an inertatmosphere to cylindrical vessel 1. Vessel 1 is insulated and containscoil 2 through which steam or a standard coolant can be circulated,depending upon whether heating or cooling of the contents of vessel 1 isdesired. The inert atmosphere may be nitrogen. The catalyst exists invessel 1 as a fluid bed 3. The particle size distribution of thecatalyst is such that it will permit adequate fiuidization so thatefiicient and uniform contacting of the catalyst particles with either apretreating gas or the hydrocarbon being converted can be maintained. Atthe lower end of vessel 1 is a support for the catalyst bed. Thissupport is made up of a grid 4, a fine screen 5 and several layers 6 and7 of different-sized Alundum beads. The catalyst must be maintainedunder an inert atmosphere, which can be nitrogen. The inert gas isintroduced into vessel 1 through lines 8 and 9 and drier 10. Such gasnot only acts as an inert atmosphere, but also operates to keep thecatalyst bed 3 fluidized. As the inert gas need not be at an elevatedtemperature at this time, heater 11 is not needed. Therefore, valves 12and 13 remain closed while valves 14, 15 and 16 remain open. Drier 10contains molecular sieves, or some other suitable desiccant, and is usedto remove moisture from the various gases which pass through it prior totheir introduction into vessel 1.

Before the catalyst is used to convert hydrocarbons, it receives apretreatment with an activating atmosphere. In this embodiment of myprocess, the activating atmosphere comprises an oxygen-containing gas.The flow of inert gas to vessel 1 is stopped by closing valve 16. Valve17 is opened and the oxygen-containing gas is passed through lines 18and 9 and drier 10 into vessel 1. The design of the vessel and theselection of the flow rate of gas should be such as to maintain asuitable fluidized catalyst bed. The fluidized bed will permit the mostetficient and uniform treatment of the catalyst.

The oxygen that is passed through the bed 3 should be held to an amountthat is slightly less than that which is required to convert half of theavailable alkali metal to its oxide. Tests have indicated that excessivetreatments in oxygen will not produce optimum catalyst activity, but itshould be noted that even the excessive oxygen treatments do result inactivity improvement. The exhaust gas will exit from vessel 1 throughline 19. When the pretreatment has been completed, valve 17 is closed.This prevents the introduction of additional oxygen-containing gas intovessel 1. Valves 14, 15, and 16 are open while valves 12 and 13 remainclosed. This permits inert gas to flow through lines 8 and 9 and drier10 into vessel 1.

Since in this specific embodiment the hydrocarbon feed will be such thatan elevated temperature of the catalyst bed 3 is not desired, heater 11will not be used. The hydrocarbon feed will be a refinery BB stream. Ifheavier hydrocarbons were used, the heater 11 would be needed. Thecatalyst bed should be cooled to a temperature of approximately 2025 F.When the catalyst bed is at the desired temperature, the hydrocarbonfeed stock is introduced into vessel 1 through drier 20, line 21, valve22 and inlet 23. The inlet 23 is so designed as to introduce thehydrocarbon without impinging it upon the sides of vessel 1. In thisembodiment, a BB stream is used as a hydrocarbon feed. The products fromthe reaction are withdrawn from vessel 1 through line 19 into aseparation zone and appropriate recovery equipment. Samples of productare removed periodically from line 19 through valve 24 and outlet 25 sothat the conversion can be monitored. When the results of appropriatetests performed on these samples indicate that the conversion has beenreduced as a result of catalyst deactivation, the run may be halted,vessel 1 opened, used catalyst withdrawn and new catalyst installed. Onthe other hand, if a second vessel is present in the installation and ishooked in parallel with vessel 1, and if this second vessel containspretreated catalyst, the hydrocarbon conversion can be switched to thissecond vessel while the catalyst in vessel 1 is changed. The parallelvessels may be operated alternately to furnish continuous operation.

What I claim is:

1. In a method for the preparation of an activated catalyst which issuitable for the isomerization of terminal olefins, which catalystcomprises an alkali metal dispersed upon an alumina support, theimprovement which comprises pretreating said catalyst by contacting itwith an activating gas selected from the group consisting of amolecular-oxygen-containing gas, nitrous oxide, mixtures thereof, andmixtures thereof with inert gases, said contacting being done at atemperature within the range between about C. and about 50 C., theamount of said activating gas being sufficient to provide at least apositive flow of said gas through said catalyst without creatingexcessive temperatures and being suflicient to provide between 0.01 and0.4 atom of oxygen per atom of alkali metal on the catalyst.

2. The method in accordance with claim 1 in which the alkali metal isselected from the group consisting of sodium, potassium, rubidium andcesium.

3. The method in accordance with claim 1 wherein said support iscalcined activated alumina.

4. The method in accordance with claim 1 wherein the amount of saidactivating gas is sufficient to provide between 0.1 and 0.4 atom ofoxygen per atom of alkali metal.

5. The process for the shifting of the double bond in a terminalolefinic hydrocarbon to a more-centrally-located position, which processcomprises contacting an olefinic hydrocarbon containing at least 4carbon atoms with a supported alkali-metal catalyst at a temperaturebetween about -80 C. and about 100 C. and at a pressure which is lessthan about 350 p.s.i.g., said catalyst being prepared by dispersing amolten alkali metal upon an alumina support and contacting the resultantcatalyst with an activating gas which is selected from the groupconsisting of a molecular oxygen-containing gas, nitrous oxide, mixturesthereof, and mixtures thereof with inert gases, said contacting beingdone at a temperature within the range between about 5 C. and about 50C., the amount of said activating gas being sufiicient to provide atleast a positive flow of said gas through said catalyst without creatingexcessive temperatures and being suflicient to provide between 0.01 and0.4 atom of oxygen per atom of alkali metal on the catalyst.

6. The process in accordance with claim 5 in which the alkali metal isselected from the group consisting of sodium, potassium, rubidium, andcesium.

7. The process in accordance with claim 5 in which the support of saidcatalyst is calcined activated alumina.

8. The process in accordance with claim 5 wherein the amount of saidactivating gas is suflicient to provide between 0.1 and 0.4 atom ofoxygen per atom of alkali metal on the catalyst.

9. A process for the shifting of the double bond in a five-carbon-atomterminal olefinic hydrocarbon to a morecentrally-located position, whichprocess comprises contacting said olefinic hydrocarbon with a supportedalkalimetal catalyst at a temperature between about C. and about C. andat a pressure which is less than about 350 p.s.i.g., said catalyst beingprepared by dispersing molten sodium metal upon a calcined activatedalumina and contacting the resultant material with an activating gaswhich is selected from the group consisting of amolecular-oxygen-containing gas, nitrous oxide, mixtures thereof, andmixtures thereof with inert gases, said contacting the resultantmaterial being done at a temperature within the range between about 5C., and about 50 C., the amount of said activating gas being sufficientto provide between 0.01 and 0.4 atom of oxygen per atom of sodium on thecatalyst.

10. The process in accordance with claim 9 wherein the amount of saidactivating gas is suflicient to provide between 0.1 and 0.4 atom ofoxygen per atom of sodium on the catalyst.

References Cited UNITED STATES PATENTS 2,994,727 8/1961 Appell et al.260-6832 DELBERT E. GANTZ, Primary Examiner.

V. OKEEFE, Assistant Examiner.

